1. Field of the Invention
This invention relates to a method for encapsulating waste and for permanently rendering the waste non-leachable and to allow permanent disposal in an environmentally safe manner.
2. Brief Description of the Prior Art
For centuries waste and refuse, both benign and dangerous, have been disposed of directly into landfills without significant concern about the environment. Even when treated prior to disposal, such as by encapsulation in either glass or cement, leaching of hazardous materials into the earth and ground water has occurred. The Kidron Valley of Biblical times has to be the most famous and probably the largest landfill in the world in use for thousands of years to receive all kinds of waste. Soils, meaning gravel, clay, sand, silt and gangues containment with all kinds of organic and inorganic materials have frequently been left as created, contaminated at the scene of the crime. Today, fortunately, efforts and methods are being explored to remove the contaminates from the ground or at least to prevent the escape of them through leaching by water. Some attempts include cleaning the soil or other waste with chemicals, encapsulating the waste in glass or in cement, or incinerating the waste or contaminated refuse. However, each of these methods are problematic. A method for cement encapsulation is taught in U.S. Pat. No. 3,980,558, for example. There are many others. The methods for treating contaminated soils are expensive because chemicals and significant labor must be utilized to clean the contaminated soil or waste, and there still is a residue to deal with. Moreover, the "throughput" of such processes is relatively low. For example, U.S. Pat. No. 5,055,196, issued to Darian, et al., teaches a process for treating soil and sludge for removal of contaminates in contact with the soil or sludge. In particular, metal or metal salts or organic contaminates such as PCBs are removed from water-wet soil and sludge by contacting the contaminated water-wet mixture with a solvent containing a comminuting surfactant. The difficult problems associated with disposal of that single waste, PCB contaminated wet soil, discussed in the '196 patent is ample evidence of the gargantuan effort required to address the environmental issues related to isolation, disposal and immobilization--making sure it stays put--of contaminated solids.
As another example, U.S. Pat. No. 5,115,986, issued to Bateson, et al., discloses a flotation process for purifying soil contaminated with organic materials in a specially adapted device which is used to "scrub" the contaminated soil. This invention has several drawbacks, one being that it discharges highly contaminated froth which must then be treated or recycled, trading one environmental problem for another. Moreover, the process is relatively slow and has a relatively low throughput. Finally, it is not clear that this process sufficiently cleans hazardous waste sufficiently to allow for the disposal of the waste in the ground without fear of leaching of contamination.
The other methods of treating waste for permanent storage represent a multitude of specialized problems. Encapsulating waste in glass or cement is expensive because of low throughput rates, as well as the logistic problems resulting from the weight of the finished product. Encapsulating in cement is especially problematic in that cement is porous and susceptible to leaching. Moreover, cement may disintegrate over time thereby allowing the waste to become mobile. Thus, a leachable waste normally is not effectively encapsulated in cement because of its porous nature as well as because of its potential for disintegration over time. Thus, there is no single process capable of treating many different types of waste. As an alternative to treating waste, incinerating contaminated refuse or waste does not yield ideal results. Incineration not only creates air pollution, but also consumes significant amounts of energy. Because of these drawbacks, waste, refuse, radioactive materials and contaminated soils (hereinafter, collectively referred to as "waste"), have traditionally been treated only when the hazardous nature of the waste, or when the effect of the environmental pollution, justified the high cost.
Wastes requiring safe disposal occur in many different forms, most readily recognizable as solid, liquid or gaseous wastes and mixtures. Often solids are contaminated with volatile liquids which, in some part, may be treated as the soils were treated described in the patents referred to above. Often the solid itself may become a waste by virtue of having received radiation from a source created by man or the waste itself, such as from power plant rods or the debris created in the manufacture of devices which involve radiation. There are also naturally occurring radioactive materials which naturally emit radiation. Of course, once a material becomes radioactive, there is no way of effectively removing the radioactivity and, therefore, the material itself must be disposed of safely, with assurance that the waste will not migrate to some other location. Current requirements for the disposal of radioactive wastes require assurances that the disposal is secure for thousands of years. The criminal penalties for violating such regulations are extremely severe.
In recent years, even practicing what had been considered prudent disposal practices, it has been discovered that many landfills containing hazardous waste can, and frequently do, contaminate water tables and water supplies through a leaching phenomena. Many varied attempts have been made, from landfill design and monitoring systems to elaborate and expensive treatment procedures, but with only limited success. Often there is an exchange of one environmental problem for one or more other problems. The need continues and thus the present invention, involving a method of encapsulating hazardous, including nuclear, waste or refuse, contaminated soils and solids which is inexpensive, which permanently prevents mobility of waste into the soils, aquifer and water supplies has resulted.
While the effort is a mammoth undertaking and has been fought with failure, it is an object of this invention to render many waste materials, solids or liquids, immobile or isolated from the environment such that benign disposal is possible.